Genus: Only 1 flagellum emergent from canal, colourless; eyespot absent; cell body fusiform or elongated, plastic, with pronounced euglenoid movement; many species, mostly freshwater (Illustrated Guide, 1985).
Species: Cell body spindle in shape, posterior end slightly pointed, 55-60 μm long, 8 μm wide (fixed sample); a locomotive flagellum 1/3 0 1/2 of the cell body in length; paramylon bodies bar-shaped or ellipsoidal, small (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000). Cell body 70-96 μm long, 10-14 μm wide, two large paramylon bodies ring-shaped (An Illustrated Guide to Freshwater Zooplankton in Japan, 2000).
Posterior end pointed 
A. longa
posterior pointed
47 x 10 μm
Iwajuku
Gunma, 2001
A. longa
stock Giw-2, axenic
posterior pointed
44 x 9 μm
Iwajuku
Gunma, 2001
A. longa
stock Giw-1, axenic
posterior pointed
μm
Iwajuku
Gunma, 2001
